[PATCH 5.10 073/191] drm/bridge: tc358768: Disable non-continuous clock mode

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5.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dmitry Osipenko <digetx@xxxxxxxxx>

[ Upstream commit fbc5a90e82c1131869e76ce5b082693b8a75c121 ]

Non-continuous clock mode doesn't work because driver doesn't support it
properly. The bridge driver programs wrong bitfields that are required by
the non-continuous mode (BTACNTRL1 register bitfields are swapped in the
code), but fixing them doesn't help.

Display panel of ASUS Transformer TF700T tablet supports non-continuous
mode and display doesn't work at all using that mode. There are no
device-trees that are actively using this DSI bridge in upstream yet,
so clearly the broken mode wasn't ever tested properly. It's a bit too
difficult to get LP mode working, hence let's disable the offending mode
for now and fall back to continuous mode.

Tested-by: Andreas Westman Dorcsak <hedmoo@xxxxxxxxx> # Asus TF700T
Tested-by: Maxim Schwalm <maxim.schwalm@xxxxxxxxx> #TF700T
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
Reviewed-by: Robert Foss <robert.foss@xxxxxxxxxx>
Signed-off-by: Robert Foss <robert.foss@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20211002233447.1105-5-digetx@xxxxxxxxx
Stable-dep-of: 66962d5c3c51 ("drm/bridge: tc358768: Fix bit updates")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/bridge/tc358768.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index a5e7afa5e6275..8f7460f011aea 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -637,6 +637,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 {
 	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
 	struct mipi_dsi_device *dsi_dev = priv->output.dev;
+	unsigned long mode_flags = dsi_dev->mode_flags;
 	u32 val, val2, lptxcnt, hact, data_type;
 	s32 raw_val;
 	const struct drm_display_mode *mode;
@@ -644,6 +645,11 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	u32 dsiclk, dsibclk;
 	int ret, i;
 
+	if (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) {
+		dev_warn_once(priv->dev, "Non-continuous mode unimplemented, falling back to continuous\n");
+		mode_flags &= ~MIPI_DSI_CLOCK_NON_CONTINUOUS;
+	}
+
 	tc358768_hw_enable(priv);
 
 	ret = tc358768_sw_reset(priv);
@@ -779,7 +785,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 		val |= BIT(i + 1);
 	tc358768_write(priv, TC358768_HSTXVREGEN, val);
 
-	if (!(dsi_dev->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
+	if (!(mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
 		tc358768_write(priv, TC358768_TXOPTIONCNTRL, 0x1);
 
 	/* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
@@ -836,7 +842,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 
 	val |= TC358768_DSI_CONTROL_TXMD;
 
-	if (!(dsi_dev->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
+	if (!(mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
 		val |= TC358768_DSI_CONTROL_HSCKMD;
 
 	if (dsi_dev->mode_flags & MIPI_DSI_MODE_EOT_PACKET)
-- 
2.42.0






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